Internet Protocol Multimedia Subsystems (“IMS”) is an architecture framework for delivering Internet Protocol (“IP”) multimedia to mobile users, such as users of mobile devices. An IMS core network (“IMS core”) permits wireless and wireline devices to access multimedia, messaging, and voice applications and services. IMS standards and specifications have been promulgated by the 3rd Generation Partnership Project (“3GPP”™). To ease the integration of an IMS core with Internet resources, 3GPP specifications use Internet Engineering Task Force protocols within the IMS core, such as Session Initiation Protocol (“SIP”) and Diameter.
SIP is a signaling protocol used for creating, modifying and terminating two-party or multiparty sessions consisting of one or several media streams. A mobile device registers its IP address with a SIP registrar server within an IMS core by generating and sending a SIP request message with a “REGISTER” method token. Once registered, a mobile device may subsequently establish multimedia sessions via the IMS core. Standard IMS registration techniques may not permit an IMS core to ascertain the IMEI of a mobile device seeking registration. Furthermore, standard IMS registration techniques may not permit an IMS core to ascertain the hardware and software capabilities of a particular mobile device so that the IMS core may intelligently provision services to the mobile device.